Heating hydrocarbon oils



W. E. LOBO HEATING HYDROCARBON OILS Filed Sept. 29, 1934 2 Sheets-Sheet 1 l ll I'l ll ll llll l l INVENTOR. WALTER [.LUBO

A TTORNEY May 31, .1938.

Filed Sept. 29, 1934 2 Shgaets-Sheet 2 FIG.2.

JNVENTOR. WALTER E. L080 A TTORNEY Patented May 31, 1938 UNITED STATES PATENT OFFICE Gasoline Products Company,

Inc., Newark,

N. J., a corporation of Delaware Application September 29, 1934, Serial No. 746,085

8 Claims.

This invention relates in general to the heating of hydrocarbon oils and more particularly to improvements in the heating of a plurality of streams of oil in a unitary heating apparatus.

The present trend in refinery practice is to heat a plurality of streams of oil in a unitary heating apparatus. At certain stages of development it was generally considered preferable to heat each individual stream of oil to the desired temperature in a separate furnace. Furnaces are bulky and as a consequence considerable space was utilizedv Subsequent practice has shown that plural streams of oil can be more efiiciently and economically heated to the desired temperatures in a single furnace structure thus avoiding duplication of furnaces as well as conserving space.

This invention contemplates the novel method for heating a plurality of streams of oil in a unitary heating apparatus to obtain the desired temperature for each stream of oil being separately heated.

The invention will be more fully understood from the following description taken in conjunction with the accompanying drawings in which:

Figure 1 is an elevational view, partly in section, of a unitary furnace capable of carrying out the invention.

Figure 2 is a flow diagram in perspective illustrating the flow of oil through the left hand radiant heating section of the furnace shown in Figure l, the flow of oil in the right hand radiant section being opposite hand.

Referring to the drawings and more particularly to Figure 1 thereof, there is shown a unitary furnace structure I of suitable refractory setting arranged preferably in a box or rectangular shape. The furnace I may comprise separate combustion or fire chambers 2 and 3 and a common convection chamber 4, separated from each other by bridge walls 5 and 6 which form the convection heating chamber.

The combustion chamber 2 may be provided with a plurality of burners 1 adapted to burn suitable fuel, such as refinery gas. Fuel for the burners I may be introduced through a line 8 controlled by a valve 9 into a manifold H, which is connected with each of the burners l by separate pipes H. The combustion chamber 3 is likewise provided with a plurality of burners 53 also adapted to burn any suitable fuel. Fuel for the burners l3 may be introduced through a line 24 controlled by a valve 15 into a manifold l6 which is connected with each of the burners I3 by separate lines l1.

While burners have been shown only on one side of the furnace, it is to be understood that similar burners may be placed on the other side and the front of the furnace in order to supply adequate heat for each of the separate combustion chambers. Moreover, the fuel supplied to the burners through the lines 3 and I4 may be obtained from any suitable source, the lines 8 and I4 being preferably connected to the conduit feeding fuel from the source to the combustion chambers.

In accordance with this invention, a plurality of streams of oil are separately heated to the desired temperature by a novel method in a furnace of the type described. For a better understanding of the method of heating the plurality of streams of oil in a specified manner to the desired temperature, the flow of the various streams of oil through the various sections of the furnace will now be described.

A stream of oil, such as a clean distillate gas oil to be cracked, preferably under vapor phase cracking conditions, may be introduced directly into the combustion chamber 2 through an inlet line F8 from which it is passed through a section of wall tubes i9 adjacent the front wall of the furnace I, thence through a line 20 to another section of wall tubes 2 l, adjacent the bridge wall 5. From the wall tubes 2| the oil is conducted to a heating coil 22 disposed about the four walls defining the combustion chamber 2. The heating coil 22 extends to a point near the top of the bridge wall 5 from which the oil passing therethrough is conducted by means of a line 23 to roof tubes 24 disposed upon the roof of the combustion chamber 2 and extending over a portion thereof.

By controlling the extent of firing of the burners I, the oil passing through the heat absorbing tubes in the combustion chamber 2 is heated to cracking temperature upon reaching the outlet tube of the roof tubes 24. The thus heated oil at cracking temperature may be conducted from the roof tubes 24 through a line 25 to a coil section 26 positioned in the upper part of the convection heating chamber 24. The coil section 26 may extend from the bridge wall 5 to about the middle of the convection heating chamber a, as indicated by the irregular line A-B, in other words the coil section 26 occupies about half of the space in the upper part of the convection heating chamber 4. The oil in flowing through the coil section 26 is further heated to gas oil, is introduced into the combustion chamber 3 to be therein heated in a manner similar to the other stream'of oil during its passage through the tubes in the'combustion chamber 2. Similar tube arrangements are shown for conveyingthe oil through the combustion chamber 3 as in combustion chamber 2. A second stream of oil is simultaneously introduced into a line 28 from which it is passed to a section of wall tubes 29 adjacent the back wall of the furnace I and then conducted through a line 3| to another section of wall tubes 32 adjacent the bridge wall 6.

From the tubes 32 theoil is conducted to a heating coil 33 disposed about the four walls defining the combustion chamber 3. The oil after passing through the heating coil33 which extends to a point near the. top of the bridge wallfi is conducted by a line 34 to roof tubes 35 extending I ing equipment, such as a soaking drum or sepation chambers.

oveiia portion of the roofof' the combustion chamber3. The oil in passing through the tubes 7 in the combustion chamber 3 is heated, preferably under vapor phase cracking conditions, to v cracking temperature from which tubes it is conducted bya line 36 to a coil section 37, positioned in the' upper part of the convection heating' chamber 4, which extends from the bridge wall to about the middle of the convection heating chamber a as indicated by the irregular line A-B. The oil passing through the coil section 31 is' further heatedto raise the temperature thereof to the desired cracking temperature by the combustion gases passing from the combusthrough the line 2'! in a linei39, from which the merged streams are passed to suitable aftertreatrating tower, for further treatment.

i From the foregoing it will be apparent that the two streams of oil passing through the separate combustion chambers 2 and Bare heated'in each in the same manner. The heat absorbing tubes? are disposed in each ofthe combustion chambers so that only a negligible, impingement, if any, thereof by the hot products of combustion takes place thereby effecting the heating of the oil passing through the tubes in each combustion chamber mainly or preponderantly by radiant heat absorbed by the tubes. v

The combustiongases after giving up heat'to the heat absorbing tubes conveying hydrocarseparate streams of oil.

' Simultaneously'with the "passage of separate bon oil ineach of the combustion chambers pass over the top of the bridge walls. 5 and 6 through the convection heating'chamber 4. These combustion gasesby directly sweeping the coil sections 26 and 3? through which separate streams of oil are being passed heat the coil sections by convection heat and supply additional heat to' the streams of oil through the tubes in the combustion chambers 2 and 3,'another stream of oil may be introduced into the heating apparatus to be heated to the, desired temperature therein. As

7 The thus heated oil after pass- 1 a ing. through the coil section 31' passes through a line 38 and is merged with the cracked oil passing 7 shown in Figure l, a stream of oil, such as naphtha to be reformed and obtained for instance from the distillation of crude oil, may be introduced into a line M from which it is divided and passed in about equal portions through 7 lines 42 and 43.

The portion of oil passing through the line 52 may be conducted to a heating coil section 41 i positioned in the lower or cooler portion of the convection heating chamber 4. The coil section lid may extend from a point adjacent the bridge wall 5 to about the middle of the convection heating chamber 4 as indicated by the irregular line AB. The oil after passing through the heating coil section it is conducted through a line 4B5 to a heating coil 26 positioned above the heating coil 22 in the.

combustion chamber 2. The heating coil 46 is disposed about the four walls of the combustion chamber 2 and receives heat from the hot combustion gases passing through the combustion chamber 2 and the radiating hot surfaces. 'The oil after passing through the heating coil fiis conducted by means of a line 5"! to roof tubes 38 which extend in a tier arrangement along the roof of the furnace from a point above about the middle of the convection heating chamber 3 to the termination of the roof tubes 24. As

shown, the oil introduced into the roof tubes 48 above the convection heating chamber fi'flows through the tubes 43 in the lower tier to the end thereof from which it is conducted. through the tubes in the upper tier to an outlet line 59.

'The portion of oil passing through the line 7 follows a similar path on the other side of the furnace and is'conducte'd through a coil section This portion of the oil after passing through the heating section'5l' is conducted, through a line 52, to aheating coil 53 disposed above the coil-section 33 about the four walls of the combustion chamber 3 and receiving heat from the combustion gases passing therethrough and the radiating hot surfaces. The oil after passing through thelheating coil 53 is conducted through line 54 to root tubes 55, arranged in tiers and extending along the roof from a point about the middle of the convection heating chamber'to the termination of the roof tubes 35. The oil is first passed through the lower tier of roof tubes 55 and then to the upper tier thereof, the flow.

top

being similar to the flow through roof tubes 8. 7

The oil leaves the'upper tier of tubes and joins theother' stream of oil from tubes .8. in' line 29 which may be connected to a suitable evaporator or the like for further treatment of the oil.

The oil, preferably naphtha, introduced through the line it and divided for passage through the furnace in the manner described is heated to the desired temperature to accomplishreformation thereof. The tubes comprising the heating sections 4% and 5] are swept by the combustion gases passing through the convection heating chamber and are heated substantially entirely by convec tion'heat therefrom. Each of the heating coils 66 and 53 is disposed out ofithe path of the hot combustion gases in their respective combustion chambers resulting in the heating of these heatas to also be'heated preponderantly by radiant heat.

These tubes receivebut a slight amount .ing coils mainly or prepcnderantly by radiant heat. The roof tubes :38 and 55 are so positioned -70 of impingement, if any, from the combustion gases passing over the bridge walls 5 and 5. That portion oi the heating tubes 48 and 55 extending 35- 5| positioned opposite the'coil section M and oc- 1 cupying the space between it andthe bridge wall 6. 1

from a point approximately over the bridge wall to about the center of the convection heating chamber =3 absorbs radiant heat from the hot combustion gases thereby preventing this radiant heat from being reflected to the upper row of tubes in the heating coil sections 25 and 21.

Simultaneously with the heating of the other streams of oil in the manner described still another stream of oil to be processed may be heated in the unitary heating apparatus in accordance with this invention. As shown, another stream of oil, such as crude oil to be distilled, may be introduced through a line 56 a portion thereof being conducted through a line 51 and another portion thereof through a line 58. The portion of oil passing through the line 51 may be conducted through the heating coil section 59 positioned intermediate the heating coil sections 26 and 64 and extending from the bridge wall to about the middle of the convection heating chamber 4 as indicated by the irregular line A-B. The coil section 59 is directly in the path of the products of combustion passing through heating chamber 4 and is heated substantially entirely by convection heat therefrom. The oil after flowing through the heating coil section 59 and heated to the desired temperature for accomplishing the desired distillation is withdrawn through a line 6| for passage to suitable after treating equipment. The portion of oil passing through the line 58 is introduced into another coil section 62 positioned intermediate the coil sections 31 and 5| and extending from a point adjacent the bridge wall 6 to about the middle of the convection heating chamber 4. The heating coil section 62 is heated similarly to the heating coil section 59. The oil after passing through the heating coil 62 and at the desired distillation temperature is conducted by means of a line 63 to a line 64 where it merges with the other portion of oil leaving the line 6|, the thus merged stream being conducted to a suitable flash tower or fractionating zone for other treatment.

The various tubes in the furnace structure I have been shown as connected in a certain manner. For instance tube sections l9, 2|, the heating coil 22, the roof section 24 and the heating coil section 26, as well as the comparable tube sections (29, 32, 33, 35 and 31) in the combustion chamber 3 and the convection heating chamber t, have been shown as connected in parallel for providing three parallel paths for the oil passing therethrough. The tubes in the coil sections 44 and 5! have been shown as connected to form a single path for the oil passing therethrough, the oil after leaving these coil sections passing respectively to the tubes of the coil sections 46 and 53 and the roof tubes 48 and 55 which are connected in the same manner. The tubes in the coil sections 59 and 62 are shown as connected in parallel to provide two parallel passages for the stream of oil passing through each. In the arrangement as shown, the oil progresses through the coil sections 44, 5|, 59 and 62, in the convection heating chamber 4 in a direction of flow counter to the direction. of flow of combustion gases through chamber 4, while the oil in coil sections 26 and 31 progresses in the same direction of flow as that of the combustion gases.

While the tubes in the various sections of the furnace have been shown as connected in a certain manner, it is to be understood that such connections may be varied with more or less parallel paths, as the case may be, being provided by connecting more or less of the tubes in parallel or if desired a single continuous path may be provided for each stream. 'Also the direction of flow of oil through various coil sections may be varied as desired as well as the positioning of the tubes in the various chambers.

Obviously, many modifications in the mode of operation may be made without departing from the spirit of the invention which is defined in its true scope in the appended claims.

I claim:

1. The method of simultaneously heating a plurality of streams of oil in a unitary heating apparatus having separate combustion chambers defined by walls and a roof and a convection heating chamber receiving combustion gases from each of said combustion chambers which comprises, directly introducing a separate stream of oil from a source exterior to the heating apparatus into heat absorbing tubes in each of said combustion chambers and heating each stream during its passage through the tubes to an elevated temperature preponderantly by radiant heat absorbed by said tubes, thereafter passing each of said streams through heat absorbing tubes in said convection heating chamber and heating each of said streams by convection heat absorbed by said tubes, simultaneously passing other separate streams of oil through other separate heat absorbing tubes in said convection heating chamber and heating each stream by the convection heat absorbed by said tubes, thereafter passing one of said last mentioned streams through heat absorbing tubes disposed along the side walls of one of said combustion chambers and heating such stream preponderantly by radiant heat absorbed by said tubes along the walls while passing another of said streams through similarly disposed tubes in the other combustion chamber, and thereafter passing each of said streams from said side wall tubes separately through heat absorbing tubes disposed along the roof of its .respective combustion chamber and heating each preponderantly by radiant heat absorbed by said tubes along the roof.

2. The method of simultaneously heating a plurality of streams of oil in a unitary heating apparatus having separate combustion chambers defined by walls and a roof and a convection heating chamber receiving combustion gases from each of said combustion chambers which comprises, directly introducing a separate stream of oil from a source exterior to the heating apparatus into heat absorbing tubes in each of said combustion chambers and heating each stream during its passage through the tubes to an elevated temperature preponderantly by radiant heat absorbed by said tubes, thereafter passing each of said streams through heat absorbing tubes in said convection heating chamber and heating said stream by convection heat absorbed by said tubes, simultaneously passing another stream of oil through other heat absorbing tubes in said convection heating chamber and heating said stream by the convection heatabsorbed by said tubes, passing said last mentioned stream thence through heat absorbing tubes disposed along the side walls of a combustion chamber above said first-mentioned tubes and heating it preponderantly by the radiant heat absorbed by said tubes along the walls and thereafter passing said stream from said wall tubes through heat absorbing tubes disposed along the roof of a combustion chamber and heating it preponderantly by radiant heat absorbed by said tubes along the roof.

4 V 3, 'I'hemethod of simultaneously heating a pluralityof streams of oil in a unitary heating apparatus havingseparate combustion chambers de-;

, fined by walls and a roof and a convectionheating chamber receiving combustion gases from each 'of said-combustion chambers which com prises, directly introducing a. separate stream of oil from a source exterior to the heating apparatus'into heat absorbing tubes disposed along the'walls of each of the combustion chambers in the lower part thereof and heating each stream during its passage through the tubes to an elevated temperature preponderantly by radiant heat absorbed by said tubes, simultaneously pass- "ing other separate streams of oil through separate heat absorbing tubes in said convection heating chamber and heating each stream by con vection heat absorbedby'said tubes, passing one of said last mentioned streams through heat absorbing tubes disposed along the side walls of one of said combustion chambers and above the heat absorbing tubes in the lower part thereof while passing another of said streams through similarly disposed tubes in the other combustion chamber and heating each preponderantly by radiant heat absorbed by said tubes along the walls and above the tubes in the, lower part of such combustion chamber. a

4. The method of simultaneously heating a plurality ofstreams of oil in a unitary heating apparatus having separate combustion chambers defined by side walls and a roof and a convection heating chamber receiving combustion gases irom each of said combustion chambers which comprises, directly introducing. a separate stream of 7 oil from a source exterior to the'heating apparatus into heat absorbing tubes'di'sposed along the side Wallsof each of the combustion chambers in the lower part thereof and heating eachstream during its passage through the tubes to an elevated temperature preponderantly by; radiant heat absorbed by said'tubes, simultaneously passing other separate streams of 'oil through separate heat absorbing tubes in said convection heating chamber and heating each stream by convection heat absorbed by said tubes, passing one of said last mentioned streams through heat absorbing tubes disposed along the side walls of one of said com- 7 bustion' chambers and above the heat absorbing tubes in the lowerpart of suchcombustion chamher while passing another of said streams through similarly disposed tubes in the other combustion chamber and heating the stream therein prepon derantly by radiant heat absorbed by said tubes along the side walls and above the tubes in the lower part of such combustion chamber and thereafter passing said stream from said'side wall tubes last-mentioned through heat absorbing tubes dis- Y posed along the roof of such combustion chamber and heating such stream preponderantly by radiant heat absorbed by said tubes along the roof.

' 5. The method of simultaneously heating a pinrality of streamsof oil in a unitary heating apparatus having separate combustion chambers defined by side walls and a roof and a convection heating chamber receiving combustion gases from each of said combustion chambers which comprises, directly introducing a separate stream of oil from a source exterior to the heating apparatus into'heat absorbing tubes disposed along theJside walls of each of the combustion chambers in the lower part thereof and heating each stream duringits passage'through the tubesto anelevated temperature preponderantly by radi-f ant heat absorbed by said'tubes, simultaneously passing other separate streams of oil through 7 separate heat absorbing tubes in said convection heating chamber and heating each stream by convection heat absorbed by said tubes, passing one of said last mentioned streams through heat absorbing tubes disposed along the side walls of one of said combustion, chambers and above the heat absorbing tubes in the lower part of such combustion chamber while passing another of said streams through similarly disposed tubes in the other combustion chamber, heating the stream therein preponderantly by radiant heat absorbed by said tubes along the side walls and above the tubes in the lower part of such combustion chamher and thereafter passing said last mentioned stream from said sidewall tubes last-mentioned through heat absorbing tubes'disposed along the roof of such combustion chamber and extending over theconvection heating chamber and heating such stream preponderantly by radiant heat ab= sorbed by said tubes, along the roof.

6. The method of simultaneously heating a plurality of streams of oil in a unitary heating apparatus having separate combustion chambers defined by walls and a roof and a convection heating chamber receiving combustion gases from each of said combustion chambers which comprises,

directly introducing a seperate stream of oil from a source .7 exterior to the heating apparatus into heat absorbing tubes disposed along the walls of each of the combustion chambers in the lower part thereof and heating each stream during its passage through the tubes to an elevated temperature preponderantly by radiant heat absorbed by said tubes, thereafter passing each of said streams through heat absorbing tubes in said convection heating chamber and heating said strcamsby convection heat absorbed by said tubes, simultaneously passing other separatestreams of oil through separate heat absorbing tubes in said convection heating chamber and heating each stream by convection heat absorbed by said tubes, thereafter passing one of said last mentioned streams through heat absorbing tubes disy 7 posed along the side walls of oneof said combustion chambers and above the tubes in the lower part of such' combustion chamber while passing anotherof said streams through similarly disposed:

' tubes in the other combustion chamber and heating the stream therein preponderantly' by radiant heat absorbed by said tubes along the side walls and above the tubes in the lower part of such combustion chamber. 7

7. The method of simultaneously heating 'a plurality of streams of oil in a' unitaryheating apparatus having separate combustion chambers defined by side walls and a roof and a convection heating chamberreceiving combustion gases from each of said combustion chambers which comprises, directly introducing a separate stream of i oil from a source exterior to the heating apparatus into heat absorbing tubes disposed along the side Walls of'each'of the combustion chambers in the lower part thereof and heating each stream during its passage through the tubes to' ant heat absorbed by said tubes, thereafter passing each of said streams through heat absorbing tubes in said convection heating chamber and heating said streams by convection heat absorbed by said tubes, simultaneously passing other se arate streams of oil through separate heat absorbing tubes in said convection heating chamber and heating each stream by convection 'heat absorbedf an elevated temperature preponderantly by'radiby said tubes, thereafter passing one of said last mentioned streams through heat absorbing tubes disposed along the side walls of one of said combustion chambers and above the tubes in the lower part of such combustion chamber while passing another of said streams through similarly disposed tubes in the other combustion chamber, heating the stream therein preponderantly by radiant heat absorbed by said tubes along the side walls and above the tubes last-mentioned in the lower part of such combustion chamber and thereafter passing said stream from said Wall tubes above the tubes in the lower part of each of the combustion chambers through heat absorbing tubes disposed along the roof of such said combustion chamber and extending over a part of the convection heating chamber and heating such stream preponderantly by radiant heat ab sorbed by said tubes along the roof.

8. The method of simultaneously heating a plurality of streams of oil, in a unitary heating apparatus having separate combustion chambers defined by Walls and a roof and a convection heating chamber receiving combustion gases from each of said combustion chambers, which comprises passing a stream of oil directly from a source exterior to said heating apparatus through heat absorbing tubes disposed in a lower section of one of said combustion chambers and heating said stream to an elevated temperature preponderantly by radiant heat absorbed and said tubes, passing said stream thence through heat absorbing tubes disposed in a hotter section of said convectioniheating chamber and heating said stream by the convection heat absorbed by said tubes, passing another stream of oil through heat absorbing tubes disposed in a lower section of another of said combustion chambers and heating said stream to an elevated temperature preponderantly by radiant heat absorbed by said tubes, passing the latter stream thence through heat absorbing tubes disposed in a hotter section of said convection heating chamber and heating said stream by the convection heat absorbed by of said combustion chambers above the bank of 

